[1.8.x] Moved contrib.sites tests out of contrib.

Backport of d8341bf024 from master

tests/sites_tests/tests.py

@@ -2,19 +2,18 @@ from __future__ import unicode_literals
 
 from django.apps import apps
 from django.conf import settings
+from django.contrib.sites import models
+from django.contrib.sites.management import create_default_site
+from django.contrib.sites.middleware import CurrentSiteMiddleware
+from django.contrib.sites.models import Site, clear_site_cache
+from django.contrib.sites.requests import RequestSite
+from django.contrib.sites.shortcuts import get_current_site
 from django.core.exceptions import ObjectDoesNotExist, ValidationError
 from django.db.models.signals import post_migrate
 from django.http import HttpRequest
 from django.test import TestCase, modify_settings, override_settings
 from django.test.utils import captured_stdout
 
-from . import models
-from .management import create_default_site
-from .middleware import CurrentSiteMiddleware
-from .models import Site, clear_site_cache
-from .requests import RequestSite
-from .shortcuts import get_current_site
-
 
 @modify_settings(INSTALLED_APPS={'append': 'django.contrib.sites'})
 class SitesFrameworkTests(TestCase):